1. Field of Invention
The present invention relates to the field of moving aerial targets, in particular a self-propelled infrared emission aerial target having a body, a propulsion system, and an infrared radiation emission system.
2. Description of Related Art
Self-propelled aerial targets are used particularly within the framework of missile development testing or troop training and in the framework of decoying to escape a missile attack.
Some of these missiles are of the infrared guidance type, namely they seek the target by detecting its infrared signature. Then, their control surfaces are moved to guide them on a given trajectory leading to the destruction of the target.
For development of such missiles, the target described in Patent WO 9727446, which has a fuselage, propulsion systems, and infrared radiation emitters, is known. The infrared radiation emitters are comprised of a heat entity which is composed of an oil burner that heats a heat-conducting surface so that the latter emits infrared radiation.
This entity has a primary chamber having air inlets under dynamic pressure and air outlets through which the air can be evacuated to the atmosphere. The burner is in a second chamber which receives air from a first chamber and contains the burner. The burner flame heats a surface in a combustion chamber that also has a lattice enabling the flame to heat the entire surface, a mechanism for controlling the flowrate of combustion gas heating the heat-conducting surface, and also hot gas outlets located near the air inlets.
Although it is efficient, such a target has a number of drawbacks.
The first of them relates to the safety and reliability of the device. Actually, if the propulsion system does not work during the launching, while the infrared radiation emitters are working, the device may be detected by a missile and destroyed while on the ground, bringing about substantial damage and body injuries for the personnel in charge of the launching.
The second of them relates to the quality of the representation of an aircraft.
Starting from a target such as that described in Patent WO 9727446, the infrared diagram simulates in band II, namely in the lock-on range of an infrared homing device, and in band III, namely in the aircraft silhouette acquisition range, and the infrared diagram is ovoid as shown in FIG. 1.
However the infrared diagram of a real aircraft is cardioid, as shown in FIG. 2.
Thus, it can be seen that representation of the infrared signature of an aircraft is only approximative with such a target.
One of the goals of the invention is to overcome these problems by providing a safe, reliable, self-propelled target that considerably improves the infrared representativeness of the target, coming closer to that of a real aircraft.
The present invention is directed to a self-propelled, preferably jet-propelled, infrared emission aerial target having an aircraft- or missile-shaped body comprising: at least one propulsion system comprising a combustion chamber in which gases are produced and a propulsion nozzle to which combustion gases produced by the combustion chamber are supplied to propel the target; an infrared radiation emitter at an external surface of the target; and a conduit such as a pipe connecting the combustion chamber or the propulsion nozzle to the infrared radiation emitter.
In a preferred embodiment, the target contains more than one propulsion system, for example, the target can contain two propulsion systems. By using more than one propulsion system, the target may have more thrust to fly faster and/or may provide for more heat for infrared detection.
In addition, the present invention is directed to a self-propelled, preferably jet-propelled, infrared emission aerial target having an aircraft- or missile-shaped body and a nose and/or wings or control surfaces, an infrared radiation emitter, and at least one propulsion system comprising one or more conduits for feeding fuel and preferably oxidizer to a combustion chamber in which combustion gases are produced and for supplying the gases to a propulsion nozzle. The target may have at least one conduit such as a pipe connecting the combustion chamber or propulsion nozzle of the propulsion system to the nose and/or to one or more wing(s) and/or one or more control surface(s) of the target, or to one or more outside element(s) attached thereto.
In embodiments, a pipe connects the combustion chamber or propulsion nozzle of the propulsion system to a chamber located in the nose or in a wing or a control surface, or to a chamber located in an outside element attached to the target.
In particular embodiments, the target has a first pipe connecting the combustion chamber or the nozzle of the propulsion system to a chamber located in the nose of the target and a second pipe connecting the combustion chamber of the propulsion system to at least one chamber located in one of the wings or control surfaces of the target. The first and second pipes can be independent or have a common part.
In embodiments, the at least one chamber located in one of the wings or control surfaces is located at its leading edge.
In embodiments, the at least one chamber comprises a steel pipe cast in silicone graphite or cast in a high-emissivity material, or made of a metal or composite material.
In embodiments, at least one part of the chamber located in the nose is made of oxidized steel coated with graphite or cast in silicone graphite. At least one part of the chamber can also be cast in another high-emissivity material or a composite material.
In embodiments, the combustion chamber is connected to a nozzle that can be made of oxidized steel coated with graphite or cast in silicone graphite or cast in another high-emissivity material or a composite material.
In embodiments, the propulsion nozzle can have a diverging-converging section, the pipe terminating in the diverging-converging section of the nozzle.
The present invention is also directed to a method of representing the infrared signature of an aircraft or missile with the aid of a self-propelled aerial target having an aircraft- or missile-shaped body and having a nose and/or wings and/or control surfaces, a propulsion system comprising one or more conduits for feeding fuel and preferably oxidizer to a combustion chamber in which propulsion gases are produced, and an infrared radiation emitter, in which some of the propulsion gases heat all or part of the external surfaces of the target and/or attachments on the target to a temperature such that they emit infrared radiation.